Reuters and other news outlets reported this month the agencies were gearing up to investigate whether the companies misuse their market power.

The senators led by Senator Amy Klobuchar, a presidential candidate, said in the letters to FTC Chairman Joe Simons and Justice Department antitrust chief Makan Delrahim that “given the silence of the FTC and the Justice Department, the truth is that we still do not know if these investigations have actually been initiated and neither do the American people.”

The FTC declined to comment on the letter, while the Justice Department did not immediately comment on Friday.

The letters were also signed by Patrick Leahy, Richard Blumenthal, Tammy Baldwin, Edward Markey, Tina Smith and Cory Booker – another presidential candidate – who said they were encouraged by the media reports of investigations “but also somewhat troubled that such inquiries were not already well underway.”

The senators noted that both agencies typically refrain from commenting on investigations that are not public “but these circumstances are far from typical. The significant public interest in and allegations surrounding the business conduct of Big Tech and the leaks concerning the clearance process relating to potential investigations of Amazon, Apple, Facebook and Google have made these matters highly unusual.”

Reuters reported this month that the Justice Department and FTC met in recent weeks and agreed to give the Justice Department the jurisdiction to undertake potential antitrust probes of Apple and Google, while the FTC was given jurisdiction to look at Amazon and Facebook.